Optimization of the AERA data at the Pierre Auger Observatory - Developing a new interface for data handling and improving the radio reconstruction based on data measured by fluorescence telescopes
Mankind has been fascinated by the universe for a long time. Already thousand years ago observations of celestial objects were made. To get a better understanding of the universe, cosmic rays are one of the important topics to study. Those are particles reaching the Earth after traveling from outer space with nearly the speed of light. They are mainly protons but also nuclei of heavier elements up to lead are detected, also neutrinos, electrons and photons. After the discovery of cosmic rays in 1912, the sources and acceleration mechanisms of cosmic rays are still under investigation. Exploding stars, called supernova, black holes or active galactic nuclei are currently favoured. If such a high energetic particle arrives at the Earth's atmosphere, they interact with the local nuclei and a so called extensive air shower (EAS) is produced. This is a cascade of particles traveling almost with the speed of light towards ground in the direction of the incoming particle.
In the context of this topic, large experiments like the Pierre Auger Observatory were built. It uses a hybrid detection technique consisting of particle detectors measuring the particle component of EAS on the ground and fluorescence telescopes measuring the energy deposition in the atmosphere. During the recent years, the radio detection could be established as another field of research for cosmic rays emitting radio waves in the MHz and GHz range. For this purpose, the Auger Engineering Radio Array (AERA) was built. It consists of autonomous detector stations measuring the electric field strength produced by cosmic rays.
The development of a new input and especially output library named AERAROOTIOLib for radio data produced by the AERA experiment is the central subject of this work. The flexible, fully ROOT based input/output library improves the efficiency of data handling and analysis significantly. Besides reducing the data volume by 20% and speeding up the read-in part of the analysis by a factor of 5, the AERAROOTIOLib enables the production of important subsets of data for different purposes, e.g. monitoring. The output/write functionality is especially necessary to extract and analyse radio events in more details and for merging data with other detector components. The general structure of the AERAROOTIOLib, the additional AERAConverter tool, data handling and data streams used in AERA, the AERA acquisition system with its different trigger modes and the structure of radio data used in AERA are described. Furthermore, the procedure to generate and evaluate a reference dataset consisting of events measured by the fluorescence telescopes and the radio detectors is discussed. This dataset can be used as a benchmark for comparisons of different radio analyses. Adaptations for the RdObserver which is used in Offline for analysing radio data to use input values based on the reconstruction of the fluorescence telescopes and first results are shown.